DESCRIPTION: (Applicant's Abstract) Economists and psychologists who study choice have proposed that decision processes are critical to the development and persistence of addiction. Those who heavily discount the future and fail to detect the indirect, adverse consequences of their behavior will be more likely to become excessive drug users. The proposed experiments will provide new information on the relationship between decision processes and addiction and new information about the psychological correlates of decision processes. The research takes advantage of laboratory procedures used in the study of rational choice. These procedures measure the degree to which choice patterns approach the most efficient possible performance, as defined by rate of monetary earnings. The subjects will vary in terms of drug use history. Thus, it will be possible to relate drug use with decision making skills. The studies will also test whether individuals can be taught to make better decisions. These data will be used to design a curriculum for teaching decision making.